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Date:      Thu, 13 Mar 2003 09:09:15 -0600
From:      Dan Nelson <dnelson@allantgroup.com>
To:        Ted Wisniewski <ted@ness.plymouth.edu>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: MMAP 2GB Limit
Message-ID:  <20030313150914.GL2336@dan.emsphone.com>
In-Reply-To: <200303131304.h2DD4bBY046723@ness.plymouth.edu>
References:  <200303131304.h2DD4bBY046723@ness.plymouth.edu>

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In the last episode (Mar 13), Ted Wisniewski said:
> Currently mmap(2) is limited to 2GB as described in the man pages;
> does anyone know if that limitation will be lifted in the near future
> either in the 4.X branch or in the 5.X branch?  We have a package
> called "ldm" which uses mmap on large files and we are concerned
> about this limit for the future.  If someone knows and can get back
> to me it would be a big help.

You will probably want to use smaller windows (256MB say) and just map
tha areas that you need.  What happens when you want to process a 20gb
file?  The i386 only has 4gb of total addressable space, and on FreeBSD
that's shared between userland and kernel.  If you're on an alpha or
sparc CPU, then the warning in the manpage probably doesn't even apply
to you.

-- 
	Dan Nelson
	dnelson@allantgroup.com

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